With this much short history , it is difficult to diagnose the condition. Still, I feel that probably you are having tinea corporis
and tinea cruris... The disease is fungal infection
caused by dermatophytes..
Avoid to take bath with soap. You may use dettol liquid. Improve the hygiene.
Have blood tests to rule out DM,HIV and any other immunocompromised disease.
For the perfect diagnosis , you consult dermatologist
Take antifungal tablets like itraconazole for few weeks.
If there is itching, take antihistaminics.
Apply antifungal cream like miconazole clotrimazole
I feel, you may get benefit with this much treatment.
Dr. Ilyas Patel MD